1. Field of the Invention
This invention relates to protection devices and more particularly to an overheating protection device electrically coupling an electrical power source to a fluid propulsion device.
2. Background of the Invention
Fluid delivery systems require a propulsion system in which propels the fluid substance through a conduit. One such propulsion system may include a pump or compressor for creating an increase pressure. If for some reason a blockage in the conduit develops or there is a loss of the fluid substance within the conduit the pump or compressor may be damaged. The damage of the pump or compressor may be sufficient to permanently rendered the pump or compressor useless. Depending upon the utility of the fluid delivery system, substantial and irreparable harm may result to the receiver of the fluid substance. Furthermore, the cost of repairing or replacing the pump or compressor may be substantial and require long periods of time.
Various types of protection devices have been proposed by the prior art for monitoring a fluid delivery system. The following U.S. Patents are examples of attempt of the prior art to solve these problems.
U.S. Pat. No. 2,741,988 to E. J. Merritt discloses a motor driven fluid pump operative to deliver fluid through a discharge conduit and having an electric supply circuit for the motor primarily controlled by a main pressure switch responsive to the pressure in the discharge conduit. A motor protective system comprises a thermostatic switch connected in series circuit relation with the main pressure switch. A thermostatic operating device for the thermostatic switch. The thermostatic operating device is mounted in the discharge conduit and is responsive to the temperature of the fluid in the discharge conduit. A heater is operative when energized to supply heat to the fluid in the discharge conduit. A heater circuit connects the heater to the supply circuit. A second pressure switch is operative to control the operation of the heater circuit. The second pressure switch is responsive to the pressure in the discharge conduit.
U.S. Pat. No. 2,778,313 to R. H. Hill discloses a pump of the positive displacement progressing cavity type having elongated helical stator and rotor members. At least one of the members has a resilient surface portion contacting the other member and in pumping relation to therewith. The surface portion has a tendency to adhere to the other member when overheated and the pump has a tendency to overheat unless operated with an adequate supply of working material in the liquid state for proper lubrication of the rotor and stator members. An electric motor is operatively connected to the pump. Conductors are connected to the motor for supplying electric current to the motor. Magnetic switch means are interposed in the conductors for controlling the supply of current to the motor. A source of electric current energizes the switch means. A thermostat is attached to the pump and connected in circuit with the source of electric current for energizing and deenergizing the switch means in response to changes in pump temperature below or above a predetermined temperature range thereby to prevent overheating and consequent damage to the resilient surface portion.
U.S. Pat. No. 2,940,395 to R. H. Hill discloses in combination a pump unit, an electric motor unit operatively connected to the pump unit. The units are adapted to be disposed adjacent the bottom of a well. Means including a plurality of power conductors adapted to extend downwardly from the ground level to the motor unit for supplying current thereto. Control means are interposed in the power conductors and adapted to be located at the ground level for controlling the supply of electrical current to the motor unit. A control circuit for the control means includes a transformer having a primary winding adapted to be connected to a source of alternative current and a secondary winding connected in the control circuit as a energizing source therefore. A temperature responsive device is attached to the motor. A control conductor connects the control means to the temperature responsive device. A manually operable switch is connected in series in the control circuit and located at ground level. A connection is between the control means and one of the power conductors at the ground level. Means connect the temperature responsive device and the one power conductor adjacent the bottom of the well. The inclusion of the one power conductor in the control circuit thereby eliminates the need for the extending an additional control conductor from the ground level to the temperature responsive device at the bottom of a well.
U.S. Pat. No. 2,946,203 to R. G. Carver discloses a compressor for a refrigerating system. The combination comprises a sealed casing. A compressor unit is disposed within the lower portion of the casing. An electric motor includes a rotor and a stator disposed in the casing above the compressor for driving the compressor unit. Means conduct low-pressure refrigerant gas from the refrigerating system into the compressor unit. Means discharge compressed refrigerant gas from the compressor unit into the casing. A discharge tube conducts compressed refrigerant gas from the casing back into the refrigerating system. The discharge tube has an inlet opening in the upper portions of the casing directly over the rotor so that refrigerant gas is discharged by the compressor unit is forced to flow upwardly over the motor to cool the motor prior to being discharged from the casing. Means supply an electrical current to the motor. Thermal responsive switch means interrupt the electrical current to the motor when the thermal responsive switch means since a predetermined high temperature. A heat conductive metallic well is mounted in the upper portion of the casing and extends downwardly into the casing adjacent to the windings of the stator. The thermal responsive switch means is disposed in the metallic well so that the heat of the refrigerant gas surrounding the well is transferred through the well to the thermal responsive switch means. A heat conductive copper arm is bonded to the base of the metallic well. The copper arm extends inwardly towards the central portion of the casing and has an end portion extending downwardly adjacent the rotor so that heat dissipated by the rotor which is not carried away by the refrigerant gas is transmitted through the copper arm to the thermal responsive switch means to promote rapid response of the thermal responsive switch to heat dissipated by the rotor when the flow of refrigerant gas through the case is reduced or stopped.
U.S. Pat. No. 3,243,679 to A. F. Enemark discloses a motor protective means particularly adapted for a hermetically-sealed motor driven compressor unit for refrigerator and air conditioning units. A motor is contained in the hermetically-sealed capsule and comprises in combination, a starting relay and a motor overload protective device responsive to the temperature of the capsule. A housing has an open side. The starting relay and the overload protective device are mounted in the housing. The open side of the housing is engaged with and is supported on the capsule. The starting relay is fixedly mounted in the housing. Resilient mounting means resiliently mount the overload protection device in the housing. The resilient mounting means have sufficient force to press the temperature responsive protective device directly against the capsule.
U.S. Pat. No. 4,370,099 to E. L. Gannaway discloses a discharge gas temperature sensing corrective arrangement for a hermetic motor-compressor unit wherein a heat sensitive element is supported in a discharge muffler located remote from the compressor outlet and in good heat transfer relation with compressed gas entering the discharge muffler from the compressor outlet so that the heat sensitive element provides an indication of the temperature of that compressed gas as it enters the discharge muffler. The discharge muffler outlet is connected to a somewhat conventional refrigerating circuit and a conduit connects the discharge muffler inlet to the compressor outlet. The compressor may include a plurality of gas compressing cylinders having their respective discharge ports connected together to form a discharge gas manifold which functions as a muffler within the compressor with the conduit connected to that discharge gas manifold. The hermetic unit may include first and second casing portions which are joinable, for example, by welding about an annular region with the sensor coupling circuitry disposed entirely on one side of the plane of the annular region and sufficiently distant from that region to prevent heat damage to the circuitry during the welding operation. The conduit connecting the compressor outlet to the discharge muffler typically passes through the plane of this annular region.
U.S. Pat. No. 4,620,425 to N.J. O'Grady discloses a hermetic compressor including a resilient retainer member adapted to removably secure a thermal overload protector relative to the compressor casing. The overload protector is arranged in a housing which is adapted to engage the upper wall of the casing. The retainer member includes one end portion dimensioned to engage the housing whereby downward pressure on the retainer member secures the overload protector relative to the casing. The overload protector housing is formed to include a pair outwardly projecting leg members. A slot formed on one of the legs aligns with an opening in the other leg are engageable by a tool which is employed to exert an external force on the housing sufficient to allow removal and replacement of the thermal protector housing relative to the retainer member.
U.S. Pat. No. 5,828,287 to B. G. Nilson discloses a new Automatic Thermal Shut-Off Switch for preventing heat damage to a high pressure low volume water pump. The inventive device includes a T-shaped housing having a longitudinal cavity, a bimetallic compression spring within the cavity, a disc within cavity on top of the spring, a pin orthogonally secured to the disc, a first contact, and a second contact electrically in contact. The housing is positioned within an unused port within a pump housing and conducts the heat produced by the pump. The conducted heat expands the spring thereby forcing the pin upwardly to separate the first contact from electrically contact with the second contact.
U.S. Pat. No. 6,312,226 to Senior, Jr. et al. discloses a device and method for detecting bearing overheating in oil-lubricated turbine pumps comprising and temperature transmitting collar and infrared sensor. The temperature transmitting collar is mounted on the pump line shaft immediately adjacent to the stretch bearing, which is the top bearing in the pump system. The infrared sensor is positioned within sensing distance of the temperature transmitting collar and control circuitry is provided to warn of abnormal temperatures and to turn the pump off if temperatures continue to rise to an alarm condition.
U.S. Pat. No. 6,454,538 to Witham et al. discloses a scroll compressor with a motor protector for stopping operation of its motor should conditions be indicative of a problem. The motor protector is sensitive to elevated temperature, and stops operation of the motor should a sensed temperature exceed a predetermined maximum. The motor protector is positioned in a chamber in a rear face of a base of the non-orbiting scroll. A port extends through the base of the non-orbiting scroll to connect a motor protector chamber to a suction chamber. Electric wires connect the motor protector to the motor and extend through this same port. In some embodiments, a pressure relief valve also communicates with the motor protector chamber. In one embodiment the motor protector chamber is enclosed by a cap and the pressure relief valve is mounted in that cap. In another embodiment the pressure relief valve extends through a wall of the non-orbiting scroll. In other embodiments, a pair of mating plugs connect the protector to the motor.
U.S. Pat. No. 6,491,500 to Sun et al. discloses a scroll compressor with a motor protector mounted at a location remote from the motor. The motor protector is of the sort which operates to stop operation of the motor both when the temperatures in the scroll compressor increases, and when the electrical characteristics of the power supplied to the motor depart from those from which are expected. Preferably, the motor protector is mounted in the non-orbiting scroll. Further, the invention includes means to increase the sensitivity of this motor protector to conditions indicative of an outdoor fan failure. In several embodiments, these means include a valve which opens to communicate hot discharge pressure refrigerant over the valve. In one other embodiment, this means is a heat sink operable to take heat away from the motor protector. In this last embodiment, when the volume flow of refrigerant decreases, the amount of heat taken away also decreases.
U.S. Pat. No. 6,527,517 to Walirafen et al. discloses a pump for a coolant circuit of an internal combustion engine of a motor vehicle includes a temperature sensor integrated into the pump for detecting the temperature of the fluid flowing into a pump chamber. The temperature sensor is inserted into a recess of a pump casing of the pump. The recess produces a reduced wall thickness (d) in the region proximate the temperature sensor. The reduced wall thickness improves the heat transition through the pump casing from the fluid to the temperature sensor and reduces the outlay in terms of production. Furthermore, the temperature sensor is arranged on a carrier material common to a control of the pump so that the susceptibility of the contacting of the temperature sensor to faults is reduced.
U.S. Pat. No. 6,540,484 to Hugenroth et al. discloses a thermostat within a scroll compressor such that a thermostat switch is positioned in the non-orbiting scroll, and a body of the thermostat extends through the crankcase. The thermostat communicates with a heater associated with a motor protector circuit. Current is directed to the heater causing the heater to more promptly stop operation of the scroll compressor. A bias element holds the thermostat securely within the crankcase and non-orbiting scroll such that it will not rattle during operation. Several embodiments of the thermostat are disclosed.
U.S. Pat. No. 6,551,065 to A. Lee discloses a device to protect fans from overheating and overloading with driving current. The fan protection device of the present invention monitors the temperature and current change of the operating fan. When the temperature or the current float surpasses a predetermined value, the protection device cuts off the fan's power supply and avoids damage to the unit.
U.S. Pat. No. 6,837,688 to Kimberlin et al. discloses an apparatus for detecting the presence of an overheat condition in a fluid pump includes a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than the first pressure. A motor is positioned adjacent the pump head to drive the pump head to pressurize the fluid. A single overheat sensor senses an overheat condition in the pump head and an overheat condition in the motor. When a threshold temperature is sensed by the overheat sensor, a switch is activated to prevent operation of the motor. In one embodiment, the overheat sensor and switch are integral and may, for example, take the form of a bi-metal switch formed in the stator windings of the motor. In alternate embodiments, the overheat sensor and switch are separate.
U.S. Pat. No. 6,908,289 to Scanderbeg et al. discloses a pressure sensor subsystem measuring the pressure within a fuel pump and outputs an under-pressure signal when the measured pressure is below a predetermined threshold pressure value. A temperature sensor subsystem measures the temperature within the fuel pump and outputs an over-temperature signal when the measured temperature is above a predetermined threshold temperature value. A timing circuit monitors the pressure sensor subsystem and the temperature sensor subsystem for output of the under-pressure and over-temperature signals and outputs a pump disconnect signal when at least one of the signals is output for a prescribed time duration. A power controller disengages power from the pump upon output of a pump disconnect signal by the timing circuit.
U.S. Patent Application US 2003/0161732 to Kimberlin et al. discloses an apparatus for detecting the presence of an overheat condition in a fluid pump includes a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than the first pressure. A motor is positioned adjacent the pump head to drive the pump head to pressurize the fluid. A single overheat sensor senses an overheat condition in the pump head and an overheat condition in the motor. When a threshold temperature is sensed by the overheat sensor, a switch is activated to prevent operation of the motor. In one embodiment, the overheat sensor and switch are integral and may, for example, take the form of a bi-metal switch formed in the stator windings of the motor. In alternate embodiments, the overheat sensor and switch are separate.
Although the aforementioned prior art have contributed to the development of the art of support devices, none of these prior art patents have solved the needs of this art.
Therefore, it is an object of the present invention to provide an improved protection device for terminating operation of the pump or compressor before damage results.
Another object of this invention is to provide an improved protection device that is an expensive to manufacture and install.
Another object of this invention is to provide an improved protection device that quickly senses a change in thermal energy of the pump or compressor.
Another object of this invention is to provide an improved protection device that resists activation by other thermal energy sources other than the pump or compressor.
Another object of this invention is to provide an improved protection device that is resistant to corrosion, whether, and ultraviolet radiation.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by modifying the invention within the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.